The present invention relates to a radio wave leakage diagnosing system for an intelligent building which is constructed using an electromagnetic shielding material for the skeleton and openings such as windows and doorways so that the whole of the building is formed into an electromagnetic shielding structure.
It is general practice in intelligent buildings to utilize jointly information communicating equipment such as a composite electronic switching system, a computer, etc. for information communication with the other party inside or outside the building. As a result of an increase in value placed on information and diversification as well as individualization of need for information, there is a rapid increase in the amount of information handled. Under these circumstances, it is a problem for future intelligent buildings how to provide required information quickly at low cost. To solve this problem, there has been studied and proposed an information network adopting a data highway system that utilizes optical fiber cables, coaxial cables or the like.
However, the data highway system of the type described above needs to lay optical fiber cables or coaxial cables extend to every terminal equipment, and therefore it necessitates a floor duct and a double-floored structure for laying such cables, resulting in a considerable increase in both the cost of construction and the term of works.
If radio waves are used for information communication, no cables are needed. In such a case, however, since the radio waves may induce noises outside the intelligent building, the use of radio waves comes under the control of radio law; on the other hand, external radio waves may cause malfunction of the system.
Accordingly, the applicant of this invention has already made various propositions concerning an intelligent building which is constructed using an electromagnetic shielding material for the skeleton and openings such as windows and doorways so that the whole of the building is formed into an electromagnetic shielding structure, thereby enabling radio communication inside the building at any desired frequency without suffering from regulation by radio law.
However, even if the whole of the building is constructed as being an electromagnetic shielding structure to enable radio communication inside the building, once the electromagnetic shielding is broken at any part of the building, the radio wave which is used inside the building is released to the outside; in such a case, the released radio wave may be undesirably detected, resulting in leakage of classified information, or the released radio wave may be a disturbing wave. Further, external radio waves such as broadcast and telecast waves may intrude into the building to cause noises. Therefore, if the electromagnetic shielding is broken, it becomes impossible to effect the radio communication inside the building, resulting in a paralysis of the information transmitting function. Accordingly, it is considerably important in order to avoid such problems to find a defect or deterioration of the electromagnetic shielding in its early stage. However, it is not easy to predict a position where the electromagnetic shielding of an intelligent building will probably be broken. In particular, when the size of the building itself increases the of inspection enlarges correspondingly. For this reason, it is considered difficult to make a diagnosis as to whether or not electromagnetic shielding performance is satisfactory, and there has heretofore been no system which is capable of finding a defect or deterioration of electromagnetic shielding of intelligent buildings.